1. Field of the Invention
The present invention generally relates to earth screw anchors and, more particularly, is concerned with an earth screw anchor assembly having components which are designed to coordinate with and complement one another so as to facilitate construction of an earth screw anchor having enhanced structural integrity and enhanced capability to penetrate difficult earth conditions.
2. Description of the Prior Art
A variety of earth screw anchors have been designed for use by utilities to secure various components or structures, such as guy wires and the like, to the earth. Such earth anchors are typically powered by a drive tool for turning the anchor into secure confinement within the ground. Thus, the earth screw anchor is adapted to be driven by a source of rotational driving force into unbroken soil.
Representative examples of earth screw anchors are disclosed in U.S. Pat. Nos. 4,334,392, 4,467,575 and Re. 32,076 to Dziedzic, U.S. Pat. No. 4,981,000 to Hamilton et al, U.S. Pat. No. 5,113,626 to Seider et al and U.S. Pat. No. 5,400,788 to Hamilton et al, all of which are assigned to the assignee of the present invention. Another earth screw anchor is disclosed in U.S. Pat. No. 4,742,656 to Farmer. These earth screw anchors basically include a longitudinally extending hub, a helical blade, and a lead tip or point. The hub has upper and lower opposite axial ends and a recess provided in the upper axial end by which the anchor may be engaged and rotatably driven by the drive tool. The helical blade, which becomes the load-bearing element of the buried anchor, is affixed to and extends about and radially outwardly from the hub between the axial ends thereof. The lead point, which is the initial earth engaging and penetrating element of the anchor, extends from the lower axial end of the hub. In the above-cited U.S. Pat. No. 5,408,788 to Hamilton et al, the lead point takes the form of a spade point having a pair of opposite leading and trailing edges which converge toward one another and merge into an end tip.
The above-identified earth screw anchors work well in the typical moderate earth conditions most commonly encountered. However, many of these constructions experience difficulty in penetrating the earth in severe conditions, such as frozen or very dense soil. Consequently, a need remains for improvements in the design and construction of earth screw anchors which will provide improved earth penetration capability.